Fixture for turning or grinding ovals



June 1l, 1935. v A. J. HURT FIXTURE FOR TURNING OR GRINDING OVALS 2 Sheets-Sheet 1 Filed Feb. 27, 1934 www Mew/af? J /92/7- r.lune 11., 1935. f A, HURT 2,004,283

FIXTURE FOR TURNING OR GRINDING OVALS Filed-Feb. .'27, 1954 -2 sheetsheet 2 Patented June 1.1, 1935 UNITED FIXTURE `Fon 'rnmofon JGRI'NDING j" i HurtyDenverQColo. 4 A Application February 27, 193,4,dScrfialfNo.` 713,074 t 12 ciaImis.4 (01; 5ml-.zap

This inventionrelates 'tof a grinding `fixture for lathes or. grinding machines `forvsuppo'r-ting and `rotating an article against a grinding Wheel upon a gyrating axis so-thatthe' ground surface will `be other thancircular, and,` while particularly adaptable t for `grinding pistons Vit iswof course, not limited to this particular use.

The: principal objectof i theinventonnis to provide a highly eli'icient device for` use inxcon` junction. with the spindle of `a lathe or' grinding machine to `which a; piston or-other article lcanloe` quickly andi accuratelysattached `and A still further object is to provide means for` grinding irregular contours such as feggeshape aswell as all variationsof ovalsfand ellipses. l

Other objects and advantages reside. inthe detail construction. of the invention; which is designed Vfor simplicity, economy, .andeiicency 'I hesewllA become more apparent from the fole lowing description Y a 1 i i ,1

In the following detailed` description of the invention reference is had to the accompanying drawing which forms apart hereof. Like nu. morals refer to like parts in drawings and, throughout Inithedrawinese- .Y M v 1 i Fig, l `,is a plan View of theinvention in :place on the spindle of a typical grinding machine.

Fig. 2 is a' Vertical longitudinal section there? throughftaken on `the line, 2-' 2;,1iig.rl.

Fig. 3 is"V a side elevation partly in Asection `of the device adaptedfor turning `irregular oregg'f` shaped contours, i Y o' t i Fig, 4 is a vertical Loross-secti'ontaken Ourthe 1ine4 4,Fig.3. g i* f n lFig.` 5 is a Ihorizontal detail section through the eccentricplate employed 'with the dci/'ica ,`Fig. 6" is a rear face v iew ofthe 'c :huck-mem: ber employed in the line 6 6, Fig. 2, l

the .description. p

Fig; '1 isa detail View of the eye-10611;erripleyed` for holding the work upon thedevice: l Y

The invention lis applicable,tov any typeV lof grindingfmachine or may be :geniployed upon` a lathe adaptable for grinding. The machine to` a grinding Wheel all views` of theV device; looking ,alongfzthe l upon which it is `used of course forms nof part of thewpresent linventioni `1 'For the purposesof illustration, portions `of` a typicall grinding machine `are indicated,` such-Aas a `slide table I0 slidably mounted upon a suitablesupporting base Hm The table l0 kcarries'the` mechanism `for Y supporting and rotating a grinding spindle l2.

The usualfgrinding machine is arranged 'so that the bed l0 reciprocates transversely with `respect .during therevolution` of the spindle I2. l

, The `invention comprises ahead l5v having a socket :boss` ld hallowed to vreceive the extremity of` the spindleA` l2." "draw Abar `I3 Kis passed, through the spindle and threaded into the head VI5 so. as tordraw it `snugly over and maintain it upon the-spindle extremity` The: headcould l beattached to thespindle in any desired manner suchas' by threading,l etc.V fThe head I5 ispro-` vided with a diametrieally extending;VA dove-f tailed groovein itsfaca'for receiving a dovetailed boss I'l-formedona. chuck Jmember I6. The boss I1 lits snugly into the" dovetailed i groove `yet is suliiciently free to allow'the chuck Vmember to' be moyedidiametric'ally of the "head lli1 `The `1.re1ative movement of the head is'controlled by a..tongue,f|8 formed'on aA rocking yoke A i. .y li

. :Ihev yoke [49W: extendsdiametrically through the headmlland isHpivoted'at-the center thereof upon a laterallyextending pivotY pin 2B. Vv"IL-he tongue "l Bionthe yokefextends between two semiinla coun-1 terfboreffiziV the dover-tailedboss I'Lbset screws circular. bearing blocks ,2 l `which rest `22 are 'prfovidedl-to taketup;` any wear or llost' `motionbetween thetongue: I8 :andthe bearing blockst2l. t' t i It. can bei seen that `arrangement' any" vrocking motionfoffthe yoke I9 upon-the Vpivot :2U will `be transmitted Ato move the axis of the `chuck IB, laterally? Aofi'the, axis of the head l5 and Spindle I.2.." The rocking motion is imparted byrmeansgofanlangle plater23. The angle plate is formed zfwithxaifoot '.24 `whicliis pivoted to shapedto tiover the Stablel ID and is provided tremityaof the base 2*4 ,is swngto the right. itV

`will position the anglefplate` l23 scf that as the yoke f|95passesthe verticalpositionfit will be at right angles" toth'e axis of rotation; and at `the fslot 38 in the base 24, by means of which the angle plate may be locked in any desired position. v

The forward face of the chuck I8 is formed with a cylindrical boss 29 for receiving an adapter ring 38. Various adapter. rings are supplied with the device to adapt it to receive pistons of various diameters. All of these rings fit snugly upon the cylindrical boss 29.

In the drawings a typical piston is illustrated f at 3| with its wrist pin at 33. The piston is attached to the device by passing its wrist pin 33 through thefeye of an eye-bolt 32. The stem of they eye-bolt 32 is threaded through a rotatable nut 313 located in a counterbore in the chuck member I6. V The nut 34 is provided with bevel teeth which may be engaged by similar teeth on the extremity of a chuck key 35. The stern of the'eye-bolt'is longitudinally slotted to form a keyway `into which a key 36 projects to prevent rotation of the eye-bolt.

It can be readilyseen that by tightening the Vnut 34 with the key 35, the piston 3l will be drawn tightly against its adapter ring 30,.and the ring will be drawn tightly against the chuck I8 so as to firmly lock the piston in a position concentric with the axis of the chuck.

As thus'far described the device may be employed for grinding any desired oval or elliptical Vcross sections uniformly throughout the length of a piston. In use,the foot 24 is set to produce the desired angle on the plate 62 to give the necessary gyration. The piston. is then brought against the grinding wheel 55, :and the device started.

It will be noted that the key 38 is positioned so as to maintain the wrist pin 33 parallel with the yoke I9. Therefore the axis of the ellipse will always lie at right angles to the wrist pin so that the piston will be ground narrowerat the wrist pin bosses than at right angles thereto.

This eccentric grinding progresses .uniformly throughout the length ofthe piston.

In certain types of pistons, especially with Vpistons having a T-slot such as shown at 60 in Fig. 3, it is desirable to grind the piston with l an oval or elliptical cross section adjacent the Wrist pin or T-slot and with a round or cylindrical cross section adjacent the skirt extremity. For such Va use an eccentric dial disc 39 may be fitted into a bore through the foot 24'. The disc 39 is eccentrically pivoted at 48to the base 25 and is provided with an arm 4I vby means of which it may be rotated. If the arm 4I is swung to the leftit will cause the eccentric disc 39 to swing the forward extremity of the foot 24 to the right .soas to bring the rocker plate 23 to the broken line position of Fig. 1, and, when swung to the left, will swing the plate 23 toward the solid line position of Fig. 1.

A gauge plate 43 is mounted upon the supporting base II by means of .suitable brackets 58. This plate is provided with an adjustable plate v44 pivoted thereon at 45.` The extremity of the arm 4I carries a'roller lIIrwhich contacts portion of, the skirt of the piston is positioned opposite the grinding wheel 55 and the arm 4I is swung to the point to give the maximum desired oval. The gauge 44 is then set to contact with the roller 43, so that, when the base 25 has moved to position the grinding wheel opposite the bottom of the piston, the arm 4I will be swung inwardly sufficiently to bring the plate 23 to the broken line position. The grinding is thenstarted with the mechanism inthe position of Fig. l and as the base moves to the left the roller 4B will gradually swing the arm 4I to the left and when the `grinding wheel is opposite to the base of the piston it will be grinding a perfect circle.

In certain instances it is desired to grind the piston with an irregular or egg-shaped cross section so that it will have a larger radius on the thrust side thereof. This can be accomplished inthe present invention by installing a track plate 4'I on the face of the angle plate 23. The track plate is provided with a depressed track groove 48 in which the rollers 28 travel. The track plate is formed with flanged side slides 8| arranged to slide upon vertical shoulders 62 on the plate 23 and may be adjusted and set in any desired vertically eccentric position by means. of a knurled screw 49. When set concentric with the axis of the spindle I2, the rollers will travel in a circle so as to produce a regular elliptical grind. When set eccentrically of the axis, the effect of Ythe rollers at one side of the axisivvill be .greater than the effect at the other side soas to produce an irregular elliptical grind. The rollers 28 are positioned on relatively long roller shaftsV 58 so thatY they are free to move in and out on the yoke I9 to follow any eccentricity of the track groove 48. The plate 23 is brought into firm engagement with the rollers 28 by means of a flanged collar 5I which slips over the socket boss I4 and is clamped thereon by means of a Suitable ring nut 52 which is threaded onto the socket bossrI4. The collar I bearsv on a Vvertical line along a vertical ridge 51 formed on the plate 23 so as not to interfere with the rocking or angular movement `of the plate.

Itis desired torcall particular attention to the shape of the eye in the eye-bolt 32 which is illustrated in detail in Fig. 7. The opening in the eye of this bolt is sufciently large to accommodate the largest expected wrist pin. To-

ward the outer extremity of the eye the sides thereof converge in two similar planes 53 which will Contact with the wrist pin at two points so as to align it perfectly withV the axis of the eye opening, regardless of its size.V This is important since it is essential that axis of the ellipse be `at right angles to the wrist pin of the piston.

Whenit is desired to employ the device for straight cylindrical grinding, the plate 23 is set at a vzero or right angle position, and an aligning pin 54 may be inserted through the chuck member` I6 into the head I5 to lock the two concentric with each other. V

In order to reduce the number kof adaptor rings 30 necessary, they could be shouldered on both faces so as to receive a piston of different diameter on each face.

While a specific form of the improvement has been described and illustrated herein, it is desired to be understood that the same' may be varied, within the Vscope of the appended claims, without departing from the spirit of the invention.

`#africanas z'fHaving thus described:lthesinvention;whatfis u claimed and desired; secured :by Letters Patent` 1is:Q- ,u

spindle a head on said xture for holding wor-k to .be` ground; .andz .means forririovingusaid` head laterally `of said fixture. during eachfrevclution of said t; spindle; `fand` means `for.:causing` 4said effect during a portion of thefrevolution of, said spind1e., l l l 2. A fixture for" attachment tothe:spindle'poffa,V .grinding machine for varyingtheigdistance. bef, tween ithe workand the grindingelementv during the` rotation of saidy spindleE comprising: `a :head for attachment tnsaid` spindle;` al chuck member i carried by said headiumeansr forJattaching-the work to said chuck member; said; chuck member i being raidallyl movable upon saidhead; anzangle plate surrounding saidshead` withiits surfaceine,

clinedito the' axis of rotation; and means co-.

acting with the surface of said plate to control the lateral movement of said chuck member.`

3. A xture for attachment to the spindle of a grinding machine for varying the distance between the Work and the grinding element during the rotation of said spindle comprising: a head u for attachment to said spindle; a chuck -member l carried by `said head; means for attaching the Work to said chuck member, said chuck memberY being radially movable upon said head; an angle plate surrounding said head; a yoke fpivotally mounted in said head; a bearing memberat the extremity of said yoke adapted tocontact with .the surface of said angle plate; and a projecting member on said yoke contacting with said'` chuck member so as to move the latter in conse-` and a rocking member pivoted `in said head and operatively connected with said chuck member.V

so as to move theV latter `diametrically in consequence of the angle of said angle plate.

5. A fixture for supporting apiston upon'the extremity of a rotating spindle so as to cause said piston to simultaneously rotateand gyrate comprising: a head for attachment to said spindle; a chuck member supported by said head, said chuck member being free to move diametrically of said head; means for attaching a piston to said chuck member; an `angle plate surrounding said head; means for setting said plate at any desired angle to the axis of said spindle;

a yoke extending through said head; a pivot for said yoke at the `center of said head; Va tongue u projecting from said yoke into said chuck member so as to communicate movement thereto; contact members at the extremities of said yoke bearing against said angle plate so as to move i said chuck member in consequence of the angle..

of said angle plate. f

6. A xture for supporting a piston upon the` extremity of arotating spindle so as to cause dle;iaf chuck t member. supported said' head, said chuck Imember being; freento -movediametrilcally; of; said headrflmeansfor attaching a piston Ftowsaid. chuck member; ian.` angle. plate; Sur- `rounding eaidtheadsvmeansior settinasaid plate ,i

at any desired angle to thefaxisfofgsaid spindle; :af` yoke extending-through-fsaid head; a pivot for said yokeat the center; of.` saidiheadifaitongue fproiecting, from said, yoke i inter saidtchuck; memmeans for Vmoving to have' asrelativelygreater '..meansaforyarying the-eccentric position; of said 4eccentric platelsoxfthat said chuck member `will besmoved diametrically in consequence'rof `both `the angle of said angle platefandftheeccentricyityJ-.ofrsaideeccentriofplate; '1 f i. Arnxture for supporting' aipistcrrfuiicr'i the lQextremityoiga rotatingV spindle `sonas `to;;c`ause sa-idf piston i to i simultaneously rotate` and'A gyrate dle; a chuck member supported by said head, said chuck member being free to move diametrically of said head; means for attaching a piston to said chuckmember; an angle plate surrounding said head; means for setting said plate` at.

any desired angle tothe axis ofy said spindle; a rocking member pivoted in s aid head and operatively connected with said chuck member so asY `to move the latter diametrically in consequence j ofthe anglepof saidangle plata-bearing blocks jinsaid chuck member; and a tongue formed on said rocking member passing between'said` bearingmembers so that the movements of said rocking member `will be` communicatedtosaid chuckme'mber'through said blocks.` Y

8. A fixture for supporting a piston upon the extremity ofa rotating spindle sci as to cause said piston to simultaneously vrotate and gyrate comprising: a head for-attachment `to said spini dle; achuck member supported by said head,

said chuck member being free to move diametrically of said head; means for attaching a piston to said chuck member; an angle` plate `surrounding said-head; means for setting said` plate at` any desired angle` to the `axis of t said spindle; a rocking member pivoted in said head and contacting at its extremities with the surfacev of said-plate, ksaid rocking member being operatively connected with said chuckmember so as to move the latter diametrically in conl sequence `of the angleof said angle plate; a lfoot formed on said angle plate; a basesupporting said foot; means for locking said'l basegin a pre-set position; and means-for swinging said 1 foot on said base so as to change the angle` of 1 said angle plate. A v

` 9. A xture for supporting alpiston upon the` `extremity of a rotating spindleso as to cause said piston to simultaneously rotateand gyrate comprising: a head for attachment to said spin- `dle; a chucklmem'ber supported by said head,`

said chuckV member being `free to move dia-V metricallyiof said head; means for attaching a piston' to saidichuck' member'y-an angle plate surrounding *said head; means forH setting said plate at any desired angle tothe axis of said spindle; aI rocking member pivoted in said head `and `contacting at its "extremities with the surface of said plate,` saidrocking member being operatively connected withfsaidV chuck member so as toY move tli'eflatter diametrically in consequence' off the angle of said angle plate; a foot formed onsaid angle plate; a base support-y ing said foot; means for locking said base in a pre-set position; means forswinging said foot on said base so asvto change the angle of said angle plate; and means for actuating said means for swinging in consequence of axial movement of said base.-

10. In a xture for` grinding'piston's: Vmeans for attaching said piston tofsaid fixture comprising: a cylindrical projection on said fixture for receiving the skirtY of said piston; an eye bolt `projecting from said fixture for receiving the wrist pin of said piston, said eye-'bolt being threaded within said fixture; a nut carried in said fixture s on the threaded portion of said eye-bolt; and means for rotating. said nut from the exterior of said iixture so as to draw said piston against said fixture.

11. In' a iixture for grinding pistons: means for attaching said pistony to said iixture comprising: a cylindrical projection on saidxture for receiving the skirt of said piston; an eye bolt projecting from said fixture for receiving the wrist pin of said piston, saideye bolt being threaded Within' lsaid fixture; a nut carried in said fixture on the threaded portion of said eye bolt; means for rotating said nut from the exterior of said iixture so as todraw said piston 1 against said fixture,V the Wrist pin opening in said eye bolt lbeing larger than saidwrist pin; and two inclined surfaces in said opening for contacting said Wrist pin as said nut is tightened.

l2. In avfixture for grinding pistons: means for attaching said piston to said fixture comprising: a cylindrical projection on said iixture for receiving the skirt of said piston; an eye bolt projecting from saidxture for receiving the wrist pin of said piston, said eye bolt being threaded Within said fixture; a Vnut carried in said fixture on the threaded portion of said eye bolt; means for rotating said nut from the exterior of said xture so as to draw said piston against said iixture;V and means for preventing 20 Y rotation of said eye bolt.

- ARTHUR J. HURT. 

